Folded dipole having a direct current output



L. R. CRUMP June 28, 1960 FOLDED DIPOLE HAVING A DIRECT CURRENT OUTPUT Filed March 25, 1956 FOLDED DIPOLE HAVING A DIRECT CURRENT, OUTPUT 7 Lloyd R. Crump, Silver Spring,- Md.,-ass ig nor of one-half to George Taylor Morris Filed Mar. 23, 1956, Ser. nts73,4s7' Q -6 Claims. 11. 250-17) This invention relates to antennae for short waves.

Patented June 28,

2 u diodes are Suitable, but other types maybe used if they are comparable with the IN34. r 1 1 A first output wire 20, is connected to the midpoint 14, and a second output wire 21; is connected to the second midpoint l6, and this first dipole maybe connected by it these two wires to a transsistor oscillator 22, to radiate a signal when the dipole is excited by energy from a remote transmitter. p

The output wire 21 of the first dipole is connected to the midpoint 14, of the second dipole, and a wire 23,

I connects the midpoint 16 of the second dipole torthe It relates in particular to an antenna which contains means whereby the outputof the antenna is a d1rect current for operative connection to a control device or to a transistor oscillator to supply the direct current power to the oscillator so that it may radiate a' signal when the antenna becomes excited by radio signals from a remote transmitter. 7 I it is an object of this invention to provide an antenna in the form of a folded dipolean'd with the antenna having means therein whereby the output ofthe antenna is a direct current.

It is a further object of this invention to provide an antenna array of several folded dipoles; with each dipole havingmeans therein whereby the output is direct current and with theoutputs of the dipoles connected in series. It-is a further-object of this invention to provide a folded dipole so constructed that the output of thedipole is direct current which may be carried overan output line without itsbeing matched to the dipole.

j It is a further object of this invention to provide-an anfolded dipole by a remote transmitter.

Figure '1 is a diagrammatic showing of the folded dipole of this invention and of an antenna array of the dipoles of this invention.

Figure 2 is awiring diagram of a folded dipole of this invention energizing a radio receiver or a relay.

Figure 3 is a wiring diagram of a folded dipole of this invention energizing a transistor radio' oscillator.

In Figure 1 there is shown an 'antenna array of three folded dipoles which are arranged to extend in a horrzontal line, and with the dipoles all tuned to the same frequency and of the same length. Since all of the dipoles are alike, it will be 'sufiicient to describe one of them in detail. The first dipole 10 has its direct current output connected in series with thedirect current output of the second dipole 11, which is positioned at a distance from the first dipole equal to the length of the first dipole, and the output of the second dipole'is connected in series with the output of the third dipole 12, which is spaced from the second dipole by a distance whichis half the length of the first dipole. V I

The output of the first two dipoles is more than twic that of the first dipole alone, andthe output of the three dipoles is about seven times that of, the first dipole alone.

The first dipole 10 has a filtering capacitor 13, of around 1000 micromicrofarad capacity connecting'the midpoint 14, of one leg 15, with the midpoint 16, of the other leg 17. On the other leg 17, and immediately on either side of the capacitor connection there is inserted a first diode 18, and a second diode 19, with the diodes being connected in back-to-back relation. TyperIN34' I pacitance of around 5 microfarads.

midpoint 14, of the third dipole, and a wire24, connected to the midpoint 16, of the third dipole forms with wire 20 the output of the whole array. g I

When the dipoles are aligned in a parallel relation and along a horizontal line the directpower outputs multiply, that is, two dipoles give about .four times the power of one dipole, and three dipoles give an output of about seven times that of one alone, the falling ofi being due in part to the increased resistance of the connections.

The dipole may be connectedthrough a relay to close a battery circuit to flash a lamp-when the dipole is energiz'ed, and the battery, of course, is not being used when the dipole is not excited. h J

In Figure 3 there is shown a folded dipole 10 connected by wires 25 and 26 to a capacitor 27, which, has'Ia ca .The capacitor is connected to an oscillator, indicated generally at 22, and which comprises a transistor 28, having its base terminal 29, connected to the wire 26, and' having itseinitter terminal 30, connected also to the wire .through'a radio frequency choke 31. The collector terminal 32, of the transistor is connected through atank circuit 33, to the Other types of transistors may wire 25, and the other element 34, of the tank circuit is connected to an antenna 35.

An oscillating crystal 36 may be connected to the collector and emitter electrodes. is conventional, and the transistor shown is type PNP.

be used when due attention is paid to the polarity of the terminals.

The capacitor 27 stores the energy from the dipole 10, and stabilizes the feeding of energy to the oscillator.

It should now be clear that when the dipole 10 is energized from a remote radio transmitter, the oscillator 22 will respond with a signal of the desired frequency to indicate the presence ofthe object the dipole is attached to, if the oscillator and the dipole are on the same ob ject. The dipole array, may, of course, be substituted for the single dipole shown for convenience in illustration. Since the output wires do not have to be matched to the dipole, for they carry only direct current, the dipole antenna 10 of Figure 2, can be conveniently attached to a device at some distance, away from the dipole or dipoles, so that an indication will be given by the device or load to indicate that the dipole, or dipoles, have been energized by radio energy from a remote transmitter.

In Figure 2, the folded dipole 10 of this invention is shown connected by wires 38 and 39 to a capacitor 37, having a capacitance of the order of 5 microfarads. The wire 39, is also connected to the emitter terminal 40, of a transistor 41, and through a tuned circuit comprising an inductance 4 2, and a variable capacitor 43, to the base 45'of the transistor in series with a diode 44. The diode is' a IN34, and the'transistor is of the PNP type in the example shown. The collector terminal 46, of the transistor is connected through a switch 47, which may be thrown to connect a headset 48, in the circuit, or be thrown to connect a relay 49, in the circuit. The relay is adapted to close a circuit comprising a battery 51, and a lamp 50, or other device. The transistor circuit is energized entirely'from the dipole 10, of this invention,

The transistor oscillator and thus, when the dipole is energized by radio from a remote transmitter, the lamp will light in response to this energization of the dipole.

The distances between the dipoles may be changed slightly for best results when the proximity of objects has to be compensated for as is well understood in this art.

While in Figure 2 a transistor is shown as an amplifier so that a relatively rugged relay may be actuated, it will be obvious that a sensitive relay may be connected directly to the storage capacitor, and without using the transistor, for the output of the folded dipole is direct current.

I claim:

1. A folded dipole antenna comprising a first wire and a second wire in spaced parallel relation and connected at their ends and with said wires being located close to each other compared to the shortest wave length employed, one of said wires being interrupted at substantially its mid-point and having circuit means comprising a pair of diodes in back-to-back-relation, a capacitor connected to said one of said wires at a point between said pair of diodes and connected to an opposite point on the other of said wires, and a pair of wires to carry only direct current from said first and said second wires and connected to the terminals of said capacitor.

2. A folded dipole antenna array comprising three folded dipoles each identical to that claimed in claim 1, and each fix tuned in construction to the desired frequency with the diodes and capacitor connected, the second dipole being spaced from the first dipole a distance equal to the length of said first dipole, the third dipole being spaced from the second dipole a distance equal to half the length of the first dipole, said three dipoles having their direct current outputs connected in series circuit relation.

3. A folded dipole identical to that of claim 1, and having an external capacitor connected to said pair of wires in parallel therewith, and having a direct current load connected to said capacitor.

4. A folded dipole antenna array comprising three folded dipoles each identical to that claimed in claim 1, said dipoles being arranged in parallel to each other in a horizontal plane and having their direct current outputs connected in series.

5. A folded dipole antenna identical to that claimed in claim 1, and connected by said pair of wires to a transistor oscillator to energize said oscillator for the transmission of radio signals in response to the exciting of said folded dipole by radio energy.

6. A unitary folded dipole antenna assembly comprising a first wire and a second wire in spaced parallel relation to each other and connected together at their respective ends, and with said wires being located close to each other compared to the shortest wave length employed, one of said wires being interrupted at substantially the midpoint of its length and having circuit means comprising a pair of diodes in back-to-back-relation, a capacitor connected to said one of said wires at a point between said pair of diodes and connected to an opposite point on the other of said wires, and a pair of transmission wires connected to the terminals of said capacitor to carry direct current when said dipole is excited by radio energy without necessitating the transmission lines being matched to the dipole antenna.

References Cited in the file of this patent UNITED STATES PATENTS 1,550,571 Round Aug. 18, 1925 1,559,992 Shatter Nov. 3, 1925 1,966,491 Ferrell July 17, 1934 2,197,494 Erben Apr. 16, 1940 2,266,038 I Iinman Dec. 16, 1941 2,307,012 Barrow Jan. 5, 1943 2,543,085 Willoughby Feb. 27, 1951 2,699,493 McCullough et al. Jan. 1 1, 1955 

